The present invention relates to a colored liquid crystal electro-optical device, e.g., a display device, using color filters produced by electrodeposition or the else and a method for manufacturing the same. The invention aims to improve the orientation reliability (particularly, when the display is left standing at high temperature) of the color filters by providing a protective layer on the color filters and further providing an orientation layer on the protective layer.
FIG. 2 of the accompanying drawings illustrates an example of multicolored liquid crystal displays using electrodeposited color filters. In the drawing, reference numeral 10 represents a transparent substrate made of glass, 11 is an electrode composed of a transparent conductive film having the pattern of an arbitrary figure or character and 12 is a color filter formed by electrodeposition of an electrodepositable polymer and a pigment. The pattern of the color filters is in alignment with the electrodes 11, and the color filters 12 are colored in a plurality of desired color tones.
A method of producing color filters by electrodeposition is disclosed in the U.S. Pat. No. 4,522,691. This method affords an effective means capable of easily producing high precision color filters. Reference numeral 13 in the drawing represents an orientation film formed by printing, spin-coating or dipping a polyimide solution, 14 is another transparent electrode and 15 is another transparent substrate. A liquid crystal 16 is sandwiched between the two substrates 10 and 15 to form a liquid crystal cell. When a voltage is applied to the liquid crystal cell and the cell is then observed while being interposed between a polarizer and an analyzer, the colors of the color filters can be observed from the portions of the liquid crystal cell which are in a transmission mode, and a black color can be observed at the other portions which do not permit the transmission of light. Namely, the device is a multicolored liquid crystal display for displacing the colors of the color filters by the use of the liquid crystal as an optical shutter.
Conventionally, polyimide having its surface rubbed with a cloth or the like in a predetermined direction has been known, and has been used as a material of an orientation film for orienting the liquid crystal molecules. Polyester-melamine resins, acryl-melamine resins, and the like have also been disclosed as the materials of the electrodeposited color filters. When the polyimide film is formed on the color filter consisting of the synthetic polymer surface, polyimide itself has low adhesion to the filter. In addition, thermo-physical behaviour of the polyimide is different from that of the filter material. For these reasons, stress imposed to the interface between the polyimide and the filter is likely to be great, so that the reliability of orienting ability of the polyimide orientation film is extremely reduced, and the orienting ability is lost within about 100 hours when the film is left standing at 80.degree. C.